A high-luminance light emitting element is manufactured by a method comprising: forming a light emitting layer on a first surface of a GaP substrate including the first surface and a second surface opposed to the first surface and having an area smaller than the first area, the light emitting layer emitting light of a wavelength λ permitted to pass through the GaP substrate; forming a plurality of side surfaces on the GaP substrate to be respectively aslant by substantially the same angle to become narrower toward the second surface; and forming a plurality of depressions and protrusions as high as 0.1 λ to 3 λ on the side surfaces.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A semiconductor light emitting element comprising: a light emitting layer for emitting light of a wavelength λ by current injection; and a GaP substrate transparent to light of the wavelength λ, the GaP substrate being an off-axis (100) GaP substrate with an off-axis angle of θ (5°≦θ≦20°) along the direction, and having: a first surface on which the light emitting layer is formed; a second surface opposed to the first surface and having an area smaller than the first surface; and first to fourth side surfaces, the first and the third side surfaces being opposed to each other, the second and the fourth side surfaces being opposed to each other, the first side surface being (1-11) oriented, the second side surface being slanted from a (111) orientation, the third side surface being (11-1) oriented, the fourth side surface being slanted from a (1-1-1) orientation, the first to fourth side surfaces individually being aslant to become narrower toward the second surface and permitting part of light from the light emitting layer to be extracted externally therethrough, the first to fourth side surfaces having a plurality of depressions and protrusions along outer surfaces thereof, wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ to an upper limit equal to or lower than 3 λ.
2. A semiconductor light emitting element according to claim 1 wherein the first to fourth side surfaces are respectively aslant by substantially a same angle to become narrower toward the second surface.
3. A semiconductor light emitting element according to claim 1 wherein the light emitting layer includes an InGaAlP layer.
4. A semiconductor light emitting element according to claim 1 wherein the wavelength λ is 650 nm.
5. A semiconductor light emitting element comprising: a light emitting layer for emitting light of a wavelength λ by current injection; and a GaP substrate transparent to light of wavelength λ, the GaP substrate is a just substrate having no inclination in surface orientation and having: a first surface on which the light emitting layer is formed; a second surface opposed to the first surface and having an area smaller than the first surface; and first to fourth side surfaces, the first and the third side surfaces being opposed to each other, the second and the fourth side surfaces being opposed to each other, the first side surface being (1-11) oriented, the second side surface being (111) orientated, the third side surface being (11-1) oriented, the fourth side surface being (1-1-1) orientated, said first to fourth side surfaces individually being aslant to become narrower toward the second surface and permitting part of light from the light emitting layer to be extracted externally therethrough, the first to fourth side surfaces having a plurality of depressions and protrusions along outer surfaces thereof for enhancing light extraction efficiency and optical output, wherein the depressions and protrusions have a height in a range from a lower limit equal to or higher than 0.1 λ to an upper limit equal to or lower than 3 λ.
6. A semiconductor light emitting element according to claim 5 wherein the side surfaces are respectively aslant by substantially a same angle to become narrower toward the second surface.
7. A semiconductor light emitting element according to claim 5 wherein the light emitting layer includes an InGaAlP layer.
8. A semiconductor light emitting element according to claim 5 wherein the wavelength λ is 650 nm.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 4, 2003
October 18, 2005
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